I've heard in 广东 (guangdong) the term 三八 to mean "gossip", particularly for a woman who gossips.
Is this common throughout China, and why does it have this meaning?
Taiwanese like to use the word "三八" to describe female behavior bordering on craziness such as frivolous actions or doing reckless things. It appears that the word originates from the Cantonese or Minnan dialect, but in reality it is not. In fact, "三八" is the authentic Central Plains vocabulary.
刘福根, author of 《汉语詈词研究》 combed through "A Short History of Chinese Swear" (汉语骂詈小史) which listed "三八" as "vulgar or primitive and showing a deliberate and obstinate desire to behave in a way that is unreasonable or unacceptable". It took reference from a book 《拊掌录》 which contains the following:
張八 refers to a prostitute from the north during the Song Dynasty, widely known for her beauty and yet unrefined manners. People called her "生張八", "生" to indicate “生梗” or “生硬”. 野 who penned the above poem described himself as 魏三 because he is the third child in his family. Thus, "三八" is derived from combining "三" in 魏三 and "八" in 生張八.
Song Dynasty is the period where mass migration of people from Central Plain to Guangdong and Fujian occurred. The "三八" saying eventually crossed the Strait to Taiwan and became popularize as a swear word.
I believe it is understood throughout China, but it may sound 'Southern' to Northerners and it wouldn't be their word of choice when they want to express the same meaning.
There are two possible origins:
According to Baidu Baike, 三八 means 三八妇女节 (International Women's Day on March 8th), which is extended to refer to women in a derogatory sense, most commonly used against women who appear crazy or maliciously gossiping or interfering with other's business.
Wikipedia says it's because when China first opened trade with foreigners, the foreigners were permitted into the city on 8th, 18th and 28th of every month, locals call seeing the foreigners 三八 (the three eight's), extending to anyone who's overly interested in fresh things, peeking secrets or gossiping.
I am from Beijing. People around me all share the first explanation, but maybe people from the south find the seconds one more sensible.